Hi Michael im confused what rear cap are you refering to and where do I mount the 7 in x 7 in screen and the box that has a blue wire that has a tag back-a yellow that says left-a white that says right-a black GNDand a red power and a male port that says video out instructions say if you want hook red and blue to a fuse that is hot when you stsrt truck for camera to go on all the time when you start truck I want to put a camera on the back of my rv how do I fasten to a fiberglass sheel I want

Optional Information:
Year (other): 2012
Make (other): Dodge 2500 super duty 4x4
Model: crew cab pickup
Engine: 5.7

Already Tried:
I started with micale and ran out of space I want to set my camera up in my cab of my pickup dont have a good spot to put a 7x7 in screem then hook into mybox that has male ports for 3 cameras I want to put 1 camera by hitch so i can see backing up and run a second wire to connect to the cable coming from my camera on the back of my rv